Fishing boats and vessels are often equipped with a trolling motor for providing a relatively small amount of thrust to slowly and quietly propel the boat or vessel while an operator is fishing. Such trolling motors typically include an elongate hollow tube which is mounted to a lower propulsion unit at one end including a motor and a propeller and secured to an upper trolling motor head unit or junction box at an opposite end. The elongate tube is generally mounted to the bow or the transom (stern) of a boat by a mounting mechanism. The mounting mechanism typically allows the tube to be axially slid upward and downward to adjust the depth of the lower propulsion unit in the water and to be rotated to control the direction of thrust. Some mounting mechanisms further allow the tube and the lower propulsion unit to be pivoted about a generally horizontal axis for stowing of the trolling motor.
During fishing, underwater sonar systems or depth finders are frequently employed to locate fish. Such underwater sonar systems typically include a puck or transducer which is fastened to an exterior of the lower propulsion unit. The transducer is electrically connected to a control and display unit in the boat by means of an elongate wire extending from the transducer to the control unit. Because this wire is typically exposed below the boat, the wire is susceptible to accidental severing or damage from underwater obstructions. Moreover, when insufficient length of wire is provided, the wire frequently becomes severed during raising and lowering of the lower propulsion unit. On the other hand, if an excessive length of wire is provided, the wire has a tendency to get caught in the propeller of the lower propulsion unit or to become tangled inside the boat. Although the wire is sometimes taped to the tube to reduce slack, such taping is tedious, time consuming and only temporary in nature.
In recognition of these problems associated with the use of trolling motors and underwater sonar systems, some trolling motor systems alternatively have the sonar transducer mounted in the lower propulsion unit with the wire routed through the lower propulsion unit and through the tube to the control and display unit. However, because the wire is routed through the interior of the tube, routing of the wire requires disassembly of the trolling motor. As a result, such systems are not well suited for after market additions of an underwater sonar system to an existing trolling motor system.
In an alternative system, the trolling motor includes an elongate tube routed through the interior of the hollow tube and terminating adjacent to the lower propulsion unit. The wire is then itself routed through the hollow tube. Because the hollow tube or post of the trolling motor is frequently rotated to redirect thrust of the lower propulsion unit, the wire or the interior tube often become undesirably twisted and damaged. Moreover, the interior tube and the wire occupy valuable space within the tube which already encloses wires of the trolling motor system itself extending from the head unit to the lower propulsion unit. Increasing the diameter of the hollow interior of the tube to additionally accommodate the interior tube and wire weakens the structural strength of the tube and reduces the tube's ability to withstand accidental collisions with underwater obstructions.
Thus, there is a continuing need for a trolling motor system that may be used with an underwater sonar system, that guides and protects the wire connecting the sonar transducer to the sonar control and display unit without twisting of the wire, that does not require valuable internal space within the post or tube supporting the lower propulsion unit and that may accommodate after market additions of underwater sonar systems without substantial disassembly of the trolling motor system.